Electrochemical impedance analysis of SILAR deposited ... · PDF fileElectrochemical impedance...

Electrochemical impedance analysis of SILAR deposited Cu2SnS3

(CTS) thin film

H. D. Shelke

Research scholar, Thin Film Physics Laboratory, Department of Physics, Shivaji University,

Kolhapur-416 004 (M.S.), India.

A. M. Patil

Research scholar, Thin Film Physics Laboratory, Department of Physics, Shivaji University, Kolhapur-416 004 (M.S.), India.

A. C. Lokhande

Research scholar, Optoelectronic Convergence Research Centre, Department of Materials Science and

Engineering, Chonnam National University, Gwangju 500-757, South Korea

J. H. Kim

Professor, Optoelectronic Convergence Research Centre, Department of Materials Science and Engineering,

Chonnam National University, Gwangju 500-757, South Korea

C. D. Lokhande*

Professor, Centre for Interdisciplinary Research, D. Y. Patil University, Kolhapur-416 006 (M.S.), India.

Abstract

SILAR deposited copper tin sulfide (Cu2SnS3) thin

films were used to analyze the study of

electrochemical impedance, capacitance- voltage

characteristics and current- voltage characteristics. The photoconversion efficiency of SILAR deposited

CTS thin film-based photoelectrochemical cell

elucidate with the help of capacitance-Voltage (C-V)

Characteristics study by Mott- Schottky plot and

corresponding circuit model of the impedance spectra

of the photoelectrochemical cell.

Keywords:

Electrochemical impedance, photoelectrochemical cell, SILAR, thin film.

Introduction In recent years, many researchers have used

electrochemical impedance spectroscopy (EIS) to

explain the working of electrode, to examine the solar

cells for a photoelectric research of charge

transferring metal-doped fullerenes, for the study of

water splitting [1], and for the analysis of water

oxidation by photoelectrochemical investigations [2].

The interest in (photo) electrochemical analysis has increased due to the availability of sophisticated

instrumentation, such as electrochemical impedance

spectroscopy (EIS) [3, 4].

Although this, there are few reports on the

electrochemical analysis of chalcogenide

semiconductors. There is a great deal of interest in

research of chalcogenide semiconductors due to their

appropriate band gaps and high optical absorption

coefficients for potential application in thin film solar

cells. Chalcogenide based semiconductors such as

CdTe and Cu(In,Ga)Se2 are alternatives to Silicon in

thin film solar cells [4, 6]. CdTe have toxic Cd [7, 8], and Cu(In,Ga)Se2 have costly In and Ga [9], so much

awareness has been given to more abundant and

lower toxicity materials for thin film solar cells. The

copper based multinary compound semiconductor

materials are used as absorber materials in

photovoltaic technology. Cu2ZnSnS4 (CZTS) has

been regard as as the alternative absorber layer to

Cu(In,Ga)Se2 due to its earth abundant and eco-

friendly ingredients, optimal direct band gap of

1.45eV and high absorption coefficient in the visible

range [10, 11]. But, compositional control and

growth of single phase CZTS films are quite difficult process. The control of composition and phase

structure in Cu2SnS3 compound is more convenient

due to its fewer elements compared with CZTS.

Ternary semiconductors such as Cu-Sn-S (CTS)

belonging to I-IV-VI groups are preferred as

excellent absorber material due to high absorption

coefficient (>104 cm−1) and small band gap (0.9 to 1.5

eV) for photovoltaic cells, and as a suitable candidate

for nonlinear optical materials [12]. It is a p-type

semiconductor with band gap and optical absorption

coefficient similar to that of CZTS material which is currently being comprehensively studied in the

photoelectronic field. The Cu2SnS3 has been

synthesized by various chemical methods such as

chemical bath deposition (CBD) [13], spin coating

International Journal of Engineering Research and Technology. ISSN 0974-3154 Volume 10, Number 1 (2017) © International Research Publication House http://www.irphouse.com

578

[14], hydrothermal [15], electrodeposition [16],

successive ionic layer adsorption and reaction

(SILAR) [17], spray pyrolysis [18], hot injection

[19], solvothermal [20] etc.

Compared to other chemicals methods, SILAR is a

simple, less expensive and less time consuming

method for the deposition of semiconducting thin

films. It is also significant in the deposition of large

area thin films. In SILAR method, substrate is

sequentially dipped into the precursor solution during

the deposition process. Sufficient reaction time favors

the complete chemical reaction and hence produces

pure phase compounds without secondary phases. In

this method, deposition cycles and dipping time are key parameters for synthesis of nanoparticles to

covering films.

Based on previous work we identify that CTS

photoanode is excellent absorber material and

suitable candidate for nonlinear optical materials.

Thus, in present paper, we report the results of an EIS

study, which carried out to examine the carrier

transport properties, to determine the equivalent

circuit parameters and to analyze the performance of

the PEC cell. The current-voltage (I-V)

characteristics of PEC cell used to find out cell efficiency. Mott-Schottky plot was used to determine

flat band potential and charge carrier density of CTS

photoelectrode.

Experimental details The chemical approach apply to synthesize CTS thin

films the mixed solution of copper sulphate

(CuSO4.2H2O), tin chloride (SnCl2.2H2O) and

Triethanolamine (TEA) is utilize as the cationic precursor and sodium sulphide (Na2S.xH2O) solution

is utilize as an anionic precursor. CTS film is

deposited on conducting oxide i.e. indium doped tin

oxide (ITO) substrate. The substrate is ultrasonically

cleaned in double distilled water (DDW) for 15

minutes and then washed by acetone. In deposition

process of Cu2SnS3, TEA solution is used as a

complexing agent who binds metal cation in the

solution. The molar concentrations of CuSO4.2H2O,

SnCl2.2H2O and Na2S.xH2O in the solution are 0.2,

0.1 and 0.3 M, respectively. In the SILAR method, the substrate is immersed into separate cationic and

anionic precursor solutions for the adsorption and

reaction, and then rinsed with DDW after each

immersion to remove the loosely bound particles and

to avoid the precipitation. By repeating the cycle

described above, CTS thin film with the desired

thickness is obtained by adjusting the preparative

parameters. These films are annealed at 300 °C in a

vacuum to improve the crystallinity. The CTS films

are well adherent, uniform and blackish in color.

Materials characterization To investigate the characteristic parameters of the

CTS thin films by XRD (X-ray diffraction), EDAX

(Energy dispersive X-ray spectroscopy), XPS (X-ray

photoelectron spectroscopy), FE-SEM (field effect

scanning electron microscopy), optical absorption, Mott-Schottky, Electrochemical Impedance

spectroscopy (EIS), and current-voltage plot of PEC

cell characterization techniques is used. The XRD

patterns is recorded by a BRUKER AXS D8

Advanced model X-ray diffractometer equipped with

Cu radiation (Kα of λ= 1.54 Ǻ). The XPS analysis is

studied by using VG Multilab 2000, Thermo VG

Scientific, UK, for state confirmation of CTS

material. The morphology of the samples is analyzed

by FE-SEM (JEOL JSM-6390). Optical band gap is

determined by the UV-Visible absorption

spectroscopy analysis carried out by a (UV- 1800 Shimadzu) spectrometer. I-V characteristics of the

PEC cell were examined using a Princeton Applied

Research Potentiostat (273A) with a CTS electrode as

the working electrode. Mott- Schottky plot and EIS

study in dark and under illumination conditions was

carried out with an electrochemical workstation

model Zive-5. Zman software was used to model the

equivalent circuit from EIS.

Results and discussion Structural study Fig. 1 confirms phase formation of Cu2SnS3 material

by X-ray diffraction (XRD) pattern. After annealing

the films at 3000C in vacuum, all of the diffraction

peaks were in good match with the standard pattern

of triclinic CTS (JCPDS No.: 27-0198) observed in

Fig. 1. This annealing process increased the peak

intensities and sharpness. XRD pattern shows

remarkable texture growth along (-2 0 10) plane at 2θ

= 47.180, as evidenced by JCPDS data file card [027–0198]. In addition to few other peaks at (-2 -1 1), (-2

0 6), (-3 -2 10) and (-4 0 12) planes at 2θ = 28.360,

32.820, 55.970 and 69.010 respectively. The XRD

pattern shows good matching between observed and

standard interplanar spacing (d) values with triclinic

crystal structure. Inter planar distances (d) of the

planes, were calculated using Bragg's diffraction

condition [21]. Calculated d values are shown in

Table 1, which is comparable with standard JCPDS

data. Crystalline grain sizes (D) of the films were

evaluated using Debye–Scherrer formula [22]

D=0.9𝜆

𝛽𝐶𝑜𝑠𝜃 (1)

Where K is the shape factor taken equal to 0.9, λ is

the wavelength of the X-ray used, β is the full width

at half maximum of the peak and θ is the Bragg angle

that corresponds to the peak analyzed. The

differences between the relative X-ray diffraction


579

intensities of the samples and standard JCPDS data

show a preferential orientation, which can be

evaluated considering the texture coefficient (Tc).

The texture coefficients of the CTS thin films were

calculated using the equation

Tc(hkl) = I(hkl ) / I0(hkl )

1

𝑁 Ʃ I(hkl ) /I0(hkl )

(2)

Where, I is measured intensity, I0 is JCPDS standard

intensity, N is the reflection number. For randomly

orientated materials, Tc values of all the planes are approximately 1.While the larger values of Tc show

preferential orientation, smaller values show lack of

grains orientated in that direction [23]. Calculated Tc

values of CTS thin films are shown in Table 1. No

one secondary phase is observed within CTS

formation by using SILAR method.

Fig. 1 XRD pattern of CTS thin film.

Table 1 Standard and calculated interplanar distances

with texture coefficient values of CTS thin film

calculated from XRD Plot.

X-ray photoelectron spectroscopy (XPS) The XPS is surface receptive quantitative

spectroscopic system that measures the elemental

composition, electronic state, chemical state and

empirical formula of the elements that available

within the material. The XPS survey spectrum of

CTS thin film is shown in Fig. 2 (A). From XPS

spectroscopy, it is obvious that CTS material consists

of the Cu1+, Sn4+ and S2- elements with the

quantification of Cu2p, Sn3d and S2p core levels

peaks, respectively [24]. The Cu2p, Sn3d and S2p

core-level photoelectron spectra with the appropriate

profile for quantitative elemental composition

determination are shown in Fig. 2 (B), (C) and (D),

respectively. The binding energy of Cu 2p3/2 and Cu 2p1/2 peaks are 932.77 and 952.50 eV, respectively

[25]. The satellite peaks does not observed around

932 and 955 eV at Cu2p core level, which correspond

to the existence of copper is Cu1+ state in CTS

material [26]. The binding energies for Sn 3d5/ 2, Sn

3d3/2 and S 2p3/2 are 487.15, 495.61 and 163.36 eV,

respectively, which match well with the earlier

reports [27]. The XPS studies authenticate that

presence of Cu and Sn in +1 and +4 oxidation states,

respectively.

Fig. 2 X-ray photoelectron spectra of CTS material.

(A) Survey spectrum, (B) Cu 2p core level, (C) Sn 3d

core level and (D) S 2p core level.

FE-SEM Analysis:

Fig. 3 (A) & (B) shows FE-SEM images of CTS

films at 15,000 and 20,000X magnifications. Fig.

3(A) shows a uniform distribution of agglomerated nanocrystals i.e. it shows the complete crystal growth

over the entire surface of substrate. It shows evidence

of appreciable grain formation. The grain formation

is seen in Fig. 3(B).The uniform density, adhesion to

the substrate and compact nature of the film is

observed. It is observed that the film is homogeneous

and have dense microstructures. The film surface

looks smooth and uniform. It is well clear from the

micrographs that the particles are spherical and

adherent. It can be seen that these spherical grains are

uniformly distributed to cover the surface of the


580

https://en.wikipedia.org/wiki/Electronic_state

https://en.wikipedia.org/wiki/Chemical_state

https://en.wikipedia.org/wiki/Empirical_formula

substrate completely. In Fig. 3(B) indicate that CTS

film is composed of a dense packing of grains with

small voids, signifying uniformity of thin film

surface. A close assessment of the figures showing

that, the nature of the grains of deposited material has

a less porous nature with clusters, which consist of extremely small spherical grains, annealing at 300 0C

for an hour in vacuum, changed the nature of the

grains considerably. Also, a small crystallites growth

on compact surface is observed. Salgam et al [28]. It

is also seen that the number of bulky small grains

overlapped and combined together to form relatively

immense islands of CTS material. This type of

surface arrangement is due to the particularly small

dimensions and elevated surface energy.

Fig. 3 FESEM images of CTS-thin film at two

magnifications of (A) 15,000X and (B) 20,000X.

Optical properties: UV–visible spectra The optical absorption spectra of SILAR deposited

CTS thin film has been carry out at room temperature

from 300 to 900 nm wavelength is shown in Fig. 4.

The nature of optical shift and the value of the optical

band gap of the material can be determined using

optical absorption measurements. The CTS thin films

show wide absorption range and the covers almost

whole visible region is shown in inset of Fig.4. These

spectra revealed that the deposited CTS thin films

have high absorbance of light in the visible region,

indicating its applicability as an absorbing material in industries such as solar cell windows layer. The CTS

thin film has high absorption in the visible region

with a hump at 500 nm, which is close to the

effective band gaps of CTS thin film, making it a

good light absorbing material. The optical band gap

spectrum was plotted from the absorption spectrum.

The observed results of the film gives the indication

of samples shows nearly sharp absorption variation

around 500 nm. The optical band gap is evaluated

using the Tauc relation [29].

hυ = A(hυ - Eg)n (3)

Where, A is a constant which is associated to the effective masses allied with the valence and

conduction bands and, n depends on the nature of

transition which is identical to 1/2 for direct

transition and 2 for indirect transition. Fig. 4 shows

the linear variation of (αhυ) 2 versus (hυ), which

indicates that the material has a direct optical band

gap [30]. It is clear from the figures that optical

absorption coefficients of the films are high (~104

cm−1). The band gaps of the CTS thin films were

found to be 1.56 eV. The band gap showed a good

match with the optimal band gap for a solar cell, indicating CTS to be a capable material for thin film

solar cell applications.

Fig. 4 Band gap plot of CTS thin film. The inset in

Fig. 4 shows optical absorption spectra.

I-V Characteristics of PEC Cells

The photoelectrochemical (PEC) responses of CTS

thin film in wide potential range of 0.6 to -0.6 V

under dark and light (chopped illumination) are

observed in Fig. 5. The photovoltaic output


581

characteristics of CTS thin films are studied by

fabricating ITO/CTS/LiClO4/graphite Cell. The

solid-liquid junction for the PEC cell was formed

with the CTS electrode as the photoelectrode and

0.25 M LiClO4 (Lithium per chlorate) solution as the

electrolyte. A graphite bar was employ as the counter electrode in the cell. The current-voltage curve in a

dark state specifies a usual electrochromic response

of the CTS film due to the intercalation/

deintercalation of electrons. The current-voltage

curve in light (chopped illumination) exhibit that the

PEC response in progress to come insight the

potential range above -0.1 V is observed in Fig. 5

(B). It is well-known that the electrochromic reaction

mainly occurs at the interfaces between the working

electrode and the electrolyte. This in turn indicates

that the amount of the electrochemical reaction sites

of the CTS electrode may be evaluated by comparing current densities of the electrochromic reaction. The

PEC cell with the configuration, CTS| 0.2 M LiClO4|

graphite, was illuminated with a light of intensity 50

mW/cm2. The electrochromic current density versus

voltage curves CTS thin films is observed in Fig. 5

(A). The current density is increased under

illumination, which leading to extremely improved

electrochemical reaction sites for the CTS electrode.

The CTS semiconductor absorbs the photons with

energy equal to or greater than the band gap energy

of CTS. This causes the creation of electron-hole pairs in the depletion region and in the diffusion layer

(e- + h+). They are constraining apart by the electric

field at the edge. Electrons are drifted towards

semiconductor surface, while holes are drifted

towards bulk semiconductor from depletion region.

The photocurrent can be effectively increased due to

the development of a depletion layer and decreased

recombination centers [31]. Improved

electrochemical reaction sites are observed due to the

superior crystallinity of the film with better crystallite

size, as shown in Fig. 5. The PEC cell parameters,

such as short circuit current (Isc), open circuit voltage (Voc), maximum current (Im), maximum voltage

(Vm), were estimated for the active surface area of

1cm2 and light intensity of 50 mW/cm2 for CTS thin

films is shown in inset of Fig. 5(A) The highest

values of photo conversion efficiency 0.11% with fill

factor of 30 % are achieved by CTS thin film. As

argue in XRD and FE-SEM, a good crystalinity and

homogeneous, compact morphology reduces the

constraints of the grain boundary to construct an

easier pathway for the flow of current and by elevate

the electron diffusion length for superior photochemistry.

Fig. 5 (A) Current- voltage characteristics of the CTS

thin film and (B) shows the CTS thin films under

chopped illumination.

Electrochemical Impedance Spectroscopy (EIS)

Study of PEC Cell

Electrochemical impedance spectroscopy (EIS) has

been calculated by applying an AC potential to an

electrochemical cell and then calculate the current throughout the cell. The impedance has information

related to the phase difference, which refers to the

angle by which the current leads the voltage [32].

The impedance is a vector, describe by the phase

angle α, which can be resolved into two components.

The impedance factor in phase with the cell voltage is

describing the real part (Zreal) and the impedance

factor at 90° to the cell voltage is describing the

imaginary part (Zimag.). Determination of impedance

Z as a function of the frequency and then resolve it

into Zreal and Zimag is the method of studying the

impedance of an electrochemical circuit. These magnitudes were plotted by using two techniques i.e.

Bode plot and Nyquist Plot [33]. A plot of Zreal Vs.

Zimag for the equivalent frequency is known as the

Nyquist plot. Each point on the resulting diagram is

made up of a Z resolved in two components


582

measured at a selected frequency. Each point on the

Nyquist plot corresponds to impedance at one

frequency. There may be such 20 - 30 points each at

different frequencies.

Nyquist plots EIS is an analytical instrument for study the

photovoltaic performance of PEC cell and investigate

the changes that occur during illumination with 50

mW/cm2. Frequency dependent electrochemical

measurements of CTS thin film electrode under dark

and illumination have been carried out at room

temperature. EIS is measured in the two-electrode

method recording impedance plots include the

response of the counter electrode as well as the

photoanode. Generally, impedance data were

differentiating in the complex-plane impedance

called Nyquist diagram. The Nyquist plots for under dark and illumination of CTS thin film is revealed in

Fig. 6(A). Inset Fig. 6(A) shows the equivalent

circuit and Table 2 summarizes the equivalent circuit

parameters gained by best fitting the impedance data.

The equivalent circuit elements consist of Rs, R1,

Q1, R2 and Q2. The high frequency (corresponding

to low Z‟) intercept on the real axis (i.e., Z‟axis)

signifying the series resistance (Rs). Rs are the ohmic

series resistance of the electrode system which

provide to the electrical contact of the electrode-

electrolyte and resistivity of electrolyte solution. R1 represents the charge transfer resistance and Q1 is the

double layer capacitance at the electrode-electrolyte

interface. R2 and Q2 represents recombination charge

transfer resistance and chemical capacitance at the

electrode-electrolyte interface.

The half circle in high frequency range is resulted

from the charge transfer resistance (Rct) and the

equivalent constant phase angle element (CPE) at the

electrolyte-electrode edge. Rs values for CTS thin

film electrodes are in the range of ohms and decrease

it after illuminate the film. It is seen from Table 2

that as, under illumination, Rs decreases of from 3.72 to 1.09 Ω. The large Rs of CTS thin film under dark

condition can be attributed to the presence of natural

ligand on the CTS surface. The Rs element is related

with a high frequency response, which illustrate

minor variation after illumination, signifying that it is

independent of illumination. After illumination the

CTS electrode, film exhibited the smallest Rct and

CPE, signifying a superior catalytic movement and

bulky surface areas. The smallest charge transfer

resistance (Rct) of 37.83 Ω is observed for CTS thin

electrode indicating fast electron diffusion process under illumination. Lower Rct of the CTS electrode

expected relatively high electrical conductivity

suggesting more quick charge transfer reaction for

Li+ addition/extraction happens at the interface [34].

From Fig. 6 (A), CTS films have a single semicircle

indicating the single relaxation process (relaxation

time). The Rct value of CTS electrode under

illumination condition in aqueous electrolyte shows

lower as compared to the Rct of CTS film under dark

condition, because of Li+ ions in the 0.25M LiClO4 electrolyte plays an important role for long lifetime

of the electron [35]. The reduction in Q1 after

illumination condition of CTS electrode is

confirmation for a uniform distribution of current

through bulk electrode. While, the raise in Q2 shows

the increase in the accumulation of charges at the

interfacial region, which may be due to the chemical

capacitance of the surface trap states that are

available due to the compact nature of the film [36].

The EIS results agreed well with the photocurrent-

voltage experiments. Therefore, it is concluded that

for higher photocurrent generation, suitable electrolyte should be selected.

Bode plot

Bode phase plot provide the information of electron

life period inside the electrode-electrolyte transition.

Bode plot is nothing but phase angle against the

logarithmic frequency (log f) is observed in Fig. 6

(B). After illuminating CTS thin electrode, the phase

angles shifted to higher values (shown in Table 2)

due to the crystalinity, average grain size and surface

compactness of the electrode. The phase angle of CTS thin film under dark condition is -3.650 less than

that for the CTS thin electrode under illumination (-

2.440), shows the superior electrochemical behavior.

Bode magnitude plot exhibit that the resistance of

CTS electrode films sharply drop off in higher

frequency region, indicate distinct change in slope

with increase the conductivity [37].


583

Fig. 6 (A) Nyquist plot for electrochemical

impedance study of a PEC cell under dark and

illuminated conditions (Inset in Fig. 5 shows the

equivalent circuit of the PEC cell) and (B) shows the

Bode plot of CTS electrode in dark and under

illumination.

Table 2 Equivalent circuit parameters for EIS

analysis under dark and light conditions.

Capacitance-Voltage (C-V) Characteristics Study

by Mott- Schottky plot

The calculation of capacitance as a function of

applied voltage is observed by using Mott-Schottky

plot. The Mott- Schottky plot exposed a non-linear

relation, as represent in Fig. 7.The capacitance-voltage (C-V) characteristics of the PEC cell were

studied in the dark. The ionic adsorption, surface

roughness and non-planar interfaces on the surface of

working electrode are the probable basis for the non-

linear activities of the plot [38]. The Mott- Schottky

plot provides useful information on the

photoelectrode such as the type of conductivity,

carrier concentration (Nd) and flat band potential

(Vfb). The electrode potential Vfb, at which the band

bending is zero, was 0.62 V and carrier density was

1.18 x 1022 per cm3. The capacitance-voltage (C-V)

measurements of CTS film electrode are carried out at the interface of electrode-electrolyte at the fixed

frequency of 1 kHz in bias sweep from 0 - 0.8

V/SCE. The Mott-Schottky plots for CTS film

electrodes are shown in Fig. 8. From the Mott-

Schottky plots (1/ C2 vs. V), the best fitted straight

line gives the slope of curves. A slope with negative

photocurrent for CTS film proves the p-type

electrical conductivity of CTS electrodes [39]. For

PEC cell measurement, flat band potential (Vfb) is

significant physical parameter to study the transfer of

charge carriers at the boundary of semiconductor

electrode and electrolyte. The flat band potentials of

CTS semiconductor electrode are estimated from Mott-Schottky plot by extrapolating the curves to the

intercept with 1/C2 = 0. The value of Vfb observed in

positive side is probably due to the electronic

structure of the CTS thin film [40]. The capacitance

in the Mott-Schottky plot to the applied voltage is

associated to capacitance of space charge layer and

capacitance of double layer. The suitable Vfb and

donor concentration shows the better ability of the

CTS electrode to easier transfer of charge carrier at

the interface of electrode to electrolyte [41]. From

Fig. 7, „graded type‟ junction is observed due to the

nonlinear nature of Mott Schottky plot which attributed to the occurrence of “shallow” as well as

“deep” donor stages (density of interface state) [42].

Fig. 7 Mott-Schottky plot for the capacitance-

voltage characteristics study of PEC cell.

Conclusion

CTS thin film has been successfully deposited on

ITO conducting substrate by SILAR method. The

electrochemical impedance properties of CTS thin

films are studied by using EIS technique. X-ray

diffraction patterns confirm the formation of

nanocrystalline structure with triclinic CTS phase.

The XPS confirms presence of Cu and Sn in +1 and +4 oxidation states, respectively. Field emission

scanning electron microscopy analysis reveals that

CTS thin film has uniform morphology with

spherical grains. The photoelectrochemical

measurement exhibits that CTS film electrode shows

a power conversion efficiency of 0.11% with large

photocurrent. Electrochemical analysis reveals that

the CTS films under illumination shows lower charge


584

transfer resistance which effectively reduces the

relaxation time and take action to fast

electrochemical route. Mott-Schottky plot make

known that the suitable Vfb and donor concentration

shows the better ability of the CTS electrode to easier

transfer of charge carrier at the electrode-electrolyte interface.

Acknowledgement

Present work was supported by the Human Resources

Development program (No.20124010203180) of

Korea Institute of Energy Technology Evaluation and

Planning (KETEP) Grant funded by the Korea

government Ministry. The basic Science Research

Program through the National Research Foundation

of Korea (NRF) funded by the Ministry of Science,

ICT (NRF2015R1A2A2A01006856).

Reference

1. T. Lopes, L. Andrade, H. Riberio, A. Mendes,

Int. J. Hydrogen Energy 35 (2010) 11601.

2. B. Klahr, S. Gimenez, F. Santiago, J. Bisquert,

T. Hamann, Energy and Environmental Science,

5 (2012) 7626.

3. L. G. Chatten, J. Pharm. Biomed. Anal. 1(4)

(1983) 491.

4. R. Memming, Top. Curr. Chem. 143 (1988) 79.

5. B. Shin, O. Gunawan, Y. Zhu, N. Bojarczuk, S.

Chey, S. Guha, Prog. Photovolt Res. Appl., 21(1) (2013) 72.

6. D. Barkhouse, O. Gunawan, T. Gokmen, T.

Todorov, D. Mitzi, Prog. Photovolt Res. Appl.,

20 (2012) 6.

7. L. Baranowski, K. McLaughlin, P. Zawadzki, S.

Lany, A. Norman, H. Hempel, R. Eichberger, T.

Unold, E. Toberer and A. Zakutayev, Phys. Rev.

Applied, 4 (2015) 044017(1).

8. M. Adelifard, M. Mohagheghi, H. Eshghi, The

Royal Swedish Acad. of Sci. Physica Scripta, 85

(2012) 035603.

9. P. Fernandes, P. Salome, A. D. Cunha, J. Phys. D: Appl. Phys., 43 (2010) 1.

10. K. Wang, O. Gunawan, T. Todorov , B. Shin, S.

Chey, N. Bojarczuk, D. Mitzi, S. Guha, Appl.

Phys. Lett. 97 (2010) 143508 (3pp).

11. H. Katagiri, K. Jimbo, S. Yamada, T. Kamimura,

W. Maw, T. Fukano, T. Ito, T. Motohiro, Appl.

Phys. Express 1 (2008) 41201(2pp).

12. Z. Su, K. Sun, Z. Han, F. Liu, Y. Lai, J. Li and

Y. Liu, J. Mater. Chem., 229 (2012) 16346.

13. B. Taher, M. Alias, I. Naji, H. Alawadi, A.

Douri, Aust. J. Basic appl. Sci., 9 (2015) 406. 14. J. Han, Y. Zhou, Y. Tian, Z. Huang, X. Wang, J.

Zhong, Z. Xia, B. Yong, H. Song and J. Tang,

Front Optoelectron, 7 (2014) 37.

15. M. Shawky, A. Shenouda, El. Said, I. Ibrahim,

Int. J. Sci. Engg. Res., 6 (2015) 1447.

16. D. Berg, R. Djemour, L. Gutay, G. Zoppi, S.

Siebentritt, P. Dale, Thin Solid Films, 520

(2012) 6291.

17. Z. Su, K. Sun, Z. Han, F. Liu, Y. Lai, J. Li, Y. Liu, J. Mater. Chem., 22 (2012) 16346.

18. G. Ilari, C. Fella, C. Ziegler, A. Uhl, Y.

Romanyuk, A. Tiwari, Sol. Energy Mater. Sol.

Cells, 104 (2012) 125.

19. A. Lokhande, K. Gurav, E. Jo, M. He, C.

Lokhande, J. Kim, Opt. Mater. 54 (2016) 207.

20. F. Chen, J. Zai, M. Xu, X. Qian, J. Mater.

Chem., A1 (2013) 4316.

21. H. Yoo, J. Kim, Sol. Energy Mater. Sol. Cells 95

(2011) 239.

22. C. Wang, S. Shei, S. Chang and S. Chang,

Applied Surface Science, 388 (2016) 71. 23. S. Sohila, M. Rajalakshmi, C. Ghosh, A. Arora

and C. Muthamizhchelvan, J. Alloys. Compd.,

509 (2011) 5843

24. B. Strohmeier, D. Levden, R. Field, D. Hercules,

J. Catal., 94 (1985) 2806.

25. R. Scheer and H. Lewerenz, J. Vac. Sci. Technol.

A, 12 (1994) 56.

26. D. Tiwari, T. Chaudhuri, T. Shripathi, U.

Deshpande, V. Sathe, Appl. Phys. A, 117 (2014)

1139.

27. P. Grutsch, M. Zeller, T. Fehlner, Inorg. Chem., 12 (1976) 1431.

28. M. Saglam, A. Ateş, B. Guzeldir and O. Ozakın,

Phys. Status Solidi (A), 209 (2012) 687.

29. M. Ashokkumar and S. Muthukumaran, J. Mater.

Sci. Mater. Electron., 24(2013) 2858.

30. C. Lokhande, S. Pawar, Solid State Commun. 49

(1984) 765.

31. M. Law, L. Greene, J. Jhonson, R. Saykally, P.

Yang, Nat. Mater. 4 (2005) 455.

32. A. Bard, L. Faulkner, A John Wiley and Sons,

New York (2001) 369.

33. J. Bockris and A. Reddy, Springer, New York (2008) 1127.

34. S. Swami, N. Chaturvedi, A. Kumar, N.

Chander, V. Dutta, D.K. Kumar, A. Ivaturi, S.

Senthilarasu, H. Upadhyaya,, Phys. Chem.

Chem. Phys. 16 (2014) 23993.

35. A. Bhalerao, B. Wagh, R. Bulakhe, P.

Deshmukh, J. Shim, C. Lokhande, Journal of

Photochemistry and Photobiology-A: Chemistry,

336 (2017) 69.

36. Q. Wang, J. E. Moser, M. Gratzel, J. Phys.

Chem. B, 109 (2005) 14945. 37. S. Patil, V. Lokhande, D. Lee and C. Lokhande,

Optical Materials, 58 (2016) 418.

38. R. Mane, B. Sankpal, C. Lokhande, Mater.

Chem. Phys., 60 (1999) 196.


585

http://iopscience.iop.org/1402-4896

http://iopscience.iop.org/1402-4896/85/3

39. S. Huang, W. Luo, Z. Zou, J. Phys. D. Appl.

Phys., 46 (2013) 235108.

40. Y. Hsu, S. Lee, J. Chang, C. Tseng, K. Lee, C.

Wang, Int. J. Electrochem. Sci. 8 (2013) 11615.

41. S. Kumari, C. Tripathi, A. Singh, D. Chauhan, R.

Shrivastav, S. Dass, V. Satsangi, Curr. Sci. 91

(2006) 25.

42. A. Rajbhoj, S. Gaikwad, J. Deshmukh, V. Bhuse,

Arch. Appl. Sci. Res. 4 (2012) 9.


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